Originally Posted by sc00by4life
your post is not relevant to anything.
I understand what you're trying to do, but you need to compare the sizes that are being discussed....
235/45/17 vs 245/35/18.....
With these two tires sizes ^^ the difference on his speedo would be -2.3% ..... Or "slower" than actual speed of vehicle .... Or 1.38 mph @60mph
If the OP doesn't want much change he'd have to go with a 265-35-18 which would give a difference of -0.1%
Not significant .....